The present invention relates to a semiconductor device and a method of manufacturing the same. Particularly, the present invention relates to a technique applicable effectively to a non-leaded semiconductor device.
As semiconductor devices in which a semiconductor chip with an integrated circuit mounted thereon is sealed with resin, those of various package structures have been proposed and are available commercially. Among them, for example a semiconductor device called QFN (Quad Flat Non-Leaded Package) type is known. The QFN type semiconductor device has a package structure in which leads connected electrically to electrodes formed on a semiconductor chip are exposed as external connecting terminals from a back surface of a resin sealing body. Therefore, a planar size thereof can be reduced in comparison with a semiconductor device of a package structure in which leads connected electrically to electrodes formed on a semiconductor chip are projected from side faces of a resin sealing body and are bent in a predetermined shape, for example a semiconductor-device called QFP (Quad Flat Package) type.
A lead frame is used in manufacturing the QFN type semiconductor device. The lead frame is fabricated by punching a metallic sheet with a precision press or by etching the metallic sheet into a predetermined pattern. The lead frame has plural product forming areas partitioned by a frame body which includes an outer frame portion and an inner frame portion. In each product forming area are disposed a chip support (tab, die pad, chip mounting portion) for mounting a semiconductor chip thereon and plural leads whose one end portions face around the chip support. The chip support is supported by suspending leads extending from a frame body of the lead frame. Opposite end portions opposite to one end portions of the leads are supported by the frame body of the lead frame.
In fabricating the QFN type semiconductor device with use of such a lead frame, a semiconductor chip is fixed to the chip support of the lead frame, then electrodes formed on the semiconductor chip and the leads are electrically connected with each other through conductive wires, thereafter the semiconductor chip, wires, chip support and suspending leads are sealed with resin to form a resin sealing body, and subsequently unnecessary portions of the lead frame are cut off.
The resin sealing body in the QFN type semiconductor device is formed by a transfer molding method which is suitable for mass production. According to the transfer molding method, the resin sealing body is formed by positioning the lead frame between upper and lower dies of a molding die in such a manner that the semiconductor chip, leads, chip support, suspending leads and bonding wires are disposed in the interior of a cavity (resin fill portion) of the molding die, and by subsequent injection of a thermosetting resin into the cavity.
As to the QFN type semiconductor device, it is disclosed for example in Japanese Unexamined Patent Publication No. 2000-299400.
[Patent Literature 1]
Japanese Unexamined Patent Publication
No. 2000-299400